Remove connectivity.

Remove connectivity.

There seems to be some strange interaction between Overload and Connectivity.
Overload encourages us to not have too many defended and attacked pieces,
as this may expose us to various tactics. This feels somewhat like it is in
conflict with Connectivity, where pieces are defended preemptively.

Here I take the "pick one or the other" approach and just remove connectivity,
while strengthening the effect of Overload to compensate. The reasoning is that
if we defend our pieces preemptively, then it does get attacked, we want to do
something about it so we don't get penalized by Overload. On the other
hand, if it doesn't get attacked, then there's no need to defend it.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 27734 W: 6174 L: 6064 D: 15496
http://tests.stockfishchess.org/tests/view/5b5073bd0ebc5902bdb7ba5c

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 51606 W: 8897 L: 8827 D: 33882
http://tests.stockfishchess.org/tests/view/5b50aa900ebc5902bdb7bf29

Bench: 4658006